English

Updated Standard Model Prediction for $\varepsilon'/\varepsilon$

High Energy Physics - Phenomenology 2018-10-24 v2 High Energy Physics - Experiment High Energy Physics - Lattice

Abstract

A recent lattice evaluation of ε/ε\varepsilon'/\varepsilon, finding a 2.1 σ\sigma deviation from the experimental value, has revived the old debate about a possible ε/ε\varepsilon'/\varepsilon anomaly. The unfounded claims of a too low Standard Model prediction are based on incorrect estimates that neglect the long-distance re-scattering of the final pions in K2πK\rightarrow 2\pi. In view of the current situation, we have recently updated the Standard Model calculation, including all known short- and long-distance contributions. Our result, Re(ε/ε)=(15±7)104\text{Re}\left(\varepsilon'/\varepsilon\right) = (15 \pm 7)\cdot 10^{-4}, is in complete agreement with the experimental measurement.

Cite

@article{arxiv.1810.04904,
  title  = {Updated Standard Model Prediction for $\varepsilon'/\varepsilon$},
  author = {Hector Gisbert and Antonio Pich},
  journal= {arXiv preprint arXiv:1810.04904},
  year   = {2018}
}

Comments

8 pages, 3 figures, talk given at 21th International Conference in Quantum Chromodynamics (QCD 18), 2 - 6 July 2018, Montpellier - FR

R2 v1 2026-06-23T04:35:57.488Z